/* Copyright (c) 2020 XEPIC Corporation Limited */
/*
 * Copyright (c) 2002-2014 Michael Ruff (mruff at chiaro.com)
 *
 *    This source code is free software; you can redistribute it
 *    and/or modify it in source code form under the terms of the GNU
 *    General Public License as published by the Free Software
 *    Foundation; either version 2 of the License, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA.
 */

#include <assert.h>
#include <math.h>
#include <stdlib.h>
#include <veriuser.h>
#include <vpi_user.h>

#include "config.h"
#include "priv.h"

/*
 * some TF time routines implemented using VPI interface
 */

// On some platforms (e.g. MinGW), pow() may not always generate an
// exact integer result when supplied with integer operands. Converting
// the result to an integer before we use it seems to be enough to work
// round this issue.
static ivl_u64_t pow10u(PLI_INT32 val) { return (ivl_u64_t)pow(10, val); }

static ivl_u64_t scale(int high, int low, void *obj) {
  ivl_u64_t scaled;

  vpiHandle use_obj = obj;
  if (use_obj == 0) {
    /* If object is not passed in, then use current scope. */
    vpiHandle hand = vpi_handle(vpiScope, vpi_handle(vpiSysTfCall, 0));
    use_obj = hand;
  } else {
    /* If object IS passed in, make sure it is a scope. If
       it is not, then get the scope of the object. We need
       a scope handle to go on. */
    switch (vpi_get(vpiType, use_obj)) {
      case vpiModule:
      case vpiGenScope:
      case vpiFunction:
      case vpiTask:
      case vpiNamedBegin:
      case vpiNamedFork:
        break;
      default:
        use_obj = vpi_handle(vpiScope, use_obj);
        break;
    }
  }

  scaled = high;
  scaled = (scaled << 32) | low;
  scaled /=
      pow10u(vpi_get(vpiTimeUnit, use_obj) - vpi_get(vpiTimePrecision, 0));

  return scaled;
}

PLI_INT32 tf_gettime(void) {
  s_vpi_time timerec;
  timerec.type = vpiSimTime;
  vpi_get_time(0, &timerec);
  return scale(timerec.high, timerec.low, 0) & 0xffffffff;
}

char *tf_strgettime(void) {
  static char buf[32];
  s_vpi_time timerec;

  timerec.type = vpiSimTime;
  vpi_get_time(0, &timerec);
  if (timerec.high)
    snprintf(buf, sizeof(buf) - 1, "%u%08u", (unsigned int)timerec.high,
             (unsigned int)timerec.low);
  else
    snprintf(buf, sizeof(buf) - 1, "%u", (unsigned int)timerec.low);
  return buf;
}

PLI_INT32 tf_igetlongtime(PLI_INT32 *high, void *obj) {
  s_vpi_time timerec;
  ivl_u64_t scaled;
  timerec.type = vpiSimTime;
  vpi_get_time((vpiHandle)obj, &timerec);
  scaled = scale(timerec.high, timerec.low, obj);

  *high = (scaled >> 32) & 0xffffffff;
  return scaled & 0xffffffff;
}

PLI_INT32 tf_getlongtime(PLI_INT32 *high) { return tf_igetlongtime(high, 0); }

/*
 * This function is not defined in the IEEE standard, but is provided for
 * compatibility with other simulators. On platforms that support this,
 * make it a weak symbol just in case the user has defined their own
 * function for this.
 */
#if !defined(__CYGWIN__) && !defined(__MINGW32__)
PLI_INT32 tf_getlongsimtime(PLI_INT32 *high) __attribute__((weak));
#endif
PLI_INT32 tf_getlongsimtime(PLI_INT32 *high) {
  s_vpi_time timerec;
  timerec.type = vpiSimTime;
  vpi_get_time(0, &timerec);

  *high = timerec.high;
  return timerec.low;
}

void tf_scale_longdelay(void *obj, PLI_INT32 low, PLI_INT32 high,
                        PLI_INT32 *alow, PLI_INT32 *ahigh) {
  ivl_u64_t scaled = scale(high, low, obj);
  *ahigh = (scaled >> 32) & 0xffffffff;
  *alow = scaled & 0xffffffff;
}

void tf_unscale_longdelay(void *obj, PLI_INT32 low, PLI_INT32 high,
                          PLI_INT32 *alow, PLI_INT32 *ahigh) {
  ivl_u64_t unscaled;
  vpiHandle hand = vpi_handle(vpiScope, vpi_handle(vpiSysTfCall, 0));

  (void)obj; /* Parameter is not used. */

  unscaled = high;
  unscaled = (unscaled << 32) | low;
  unscaled *=
      pow(10, vpi_get(vpiTimeUnit, hand) - vpi_get(vpiTimePrecision, 0));

  *ahigh = (unscaled >> 32) & 0xffffffff;
  *alow = unscaled & 0xffffffff;
}

void tf_scale_realdelay(void *obj, double real, double *areal) {
  vpiHandle hand = vpi_handle(vpiScope, vpi_handle(vpiSysTfCall, 0));

  (void)obj; /* Parameter is not used. */

  *areal =
      real / pow(10, vpi_get(vpiTimeUnit, hand) - vpi_get(vpiTimePrecision, 0));
}

void tf_unscale_realdelay(void *obj, double real, double *areal) {
  vpiHandle hand = vpi_handle(vpiScope, vpi_handle(vpiSysTfCall, 0));

  (void)obj; /* Parameter is not used. */

  *areal =
      real * pow(10, vpi_get(vpiTimeUnit, hand) - vpi_get(vpiTimePrecision, 0));
}

PLI_INT32 tf_gettimeprecision(void) {
  PLI_INT32 rc;
  vpiHandle hand;
  vpiHandle sys = vpi_handle(vpiSysTfCall, 0);
  assert(sys);

  hand = vpi_handle(vpiScope, sys);
  rc = vpi_get(vpiTimePrecision, hand);

  if (pli_trace)
    fprintf(pli_trace, "tf_gettimeprecision(<%s>) --> %d\n",
            vpi_get_str(vpiName, sys), (int)rc);

  return rc;
}

PLI_INT32 tf_igettimeprecision(void *obj) {
  PLI_INT32 rc;

  if (obj == 0) {
    /* If the obj pointer is null, then get the simulation
       time precision. */
    rc = vpi_get(vpiTimePrecision, 0);

  } else {
    vpiHandle scope = vpi_handle(vpiScope, (vpiHandle)obj);
    assert(scope);
    rc = vpi_get(vpiTimePrecision, scope);
  }

  if (pli_trace)
    fprintf(pli_trace, "tf_igettimeprecision(<%s>) --> %d\n",
            obj ? vpi_get_str(vpiName, obj) : ".", (int)rc);

  return rc;
}

PLI_INT32 tf_gettimeunit() {
  vpiHandle hand = vpi_handle(vpiScope, vpi_handle(vpiSysTfCall, 0));
  return vpi_get(vpiTimeUnit, hand);
}

PLI_INT32 tf_igettimeunit(void *obj) {
  return vpi_get(!obj ? vpiTimePrecision : vpiTimeUnit, (vpiHandle)obj);
}
